/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date:        19. March 2015
* $Revision: 	V.1.4.5
*
* Project: 	    CMSIS DSP Library
* Title:	    arm_cfft_radix4_f32.c
*
* Description:	Radix-4 Decimation in Frequency CFFT & CIFFT Floating point processing function
*
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*   - Redistributions of source code must retain the above copyright
*     notice, this list of conditions and the following disclaimer.
*   - Redistributions in binary form must reproduce the above copyright
*     notice, this list of conditions and the following disclaimer in
*     the documentation and/or other materials provided with the
*     distribution.
*   - Neither the name of ARM LIMITED nor the names of its contributors
*     may be used to endorse or promote products derived from this
*     software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
* -------------------------------------------------------------------- */

#include "arm_math.h"

extern void arm_bitreversal_f32(
    float32_t *pSrc,
    uint16_t fftSize,
    uint16_t bitRevFactor,
    uint16_t *pBitRevTab);

/**
* @ingroup groupTransforms
*/

/* ----------------------------------------------------------------------
** Internal helper function used by the FFTs
** ------------------------------------------------------------------- */

/*
* @brief  Core function for the floating-point CFFT butterfly process.
* @param[in, out] *pSrc            points to the in-place buffer of floating-point data type.
* @param[in]      fftLen           length of the FFT.
* @param[in]      *pCoef           points to the twiddle coefficient buffer.
* @param[in]      twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
* @return none.
*/

void arm_radix4_butterfly_f32(
    float32_t *pSrc,
    uint16_t fftLen,
    float32_t *pCoef,
    uint16_t twidCoefModifier)
{

    float32_t co1, co2, co3, si1, si2, si3;
    uint32_t ia1, ia2, ia3;
    uint32_t i0, i1, i2, i3;
    uint32_t n1, n2, j, k;

#ifndef ARM_MATH_CM0_FAMILY_FAMILY

    /* Run the below code for Cortex-M4 and Cortex-M3 */

    float32_t xaIn, yaIn, xbIn, ybIn, xcIn, ycIn, xdIn, ydIn;
    float32_t Xaplusc, Xbplusd, Yaplusc, Ybplusd, Xaminusc, Xbminusd, Yaminusc,
              Ybminusd;
    float32_t Xb12C_out, Yb12C_out, Xc12C_out, Yc12C_out, Xd12C_out, Yd12C_out;
    float32_t Xb12_out, Yb12_out, Xc12_out, Yc12_out, Xd12_out, Yd12_out;
    float32_t *ptr1;
    float32_t p0, p1, p2, p3, p4, p5;
    float32_t a0, a1, a2, a3, a4, a5, a6, a7;

    /*  Initializations for the first stage */
    n2 = fftLen;
    n1 = n2;

    /* n2 = fftLen/4 */
    n2 >>= 2u;
    i0 = 0u;
    ia1 = 0u;

    j = n2;

    /*  Calculation of first stage */
    do
    {
        /*  index calculation for the input as, */
        /*  pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
        i1 = i0 + n2;
        i2 = i1 + n2;
        i3 = i2 + n2;

        xaIn = pSrc[(2u * i0)];
        yaIn = pSrc[(2u * i0) + 1u];

        xbIn = pSrc[(2u * i1)];
        ybIn = pSrc[(2u * i1) + 1u];

        xcIn = pSrc[(2u * i2)];
        ycIn = pSrc[(2u * i2) + 1u];

        xdIn = pSrc[(2u * i3)];
        ydIn = pSrc[(2u * i3) + 1u];

        /* xa + xc */
        Xaplusc = xaIn + xcIn;
        /* xb + xd */
        Xbplusd = xbIn + xdIn;
        /* ya + yc */
        Yaplusc = yaIn + ycIn;
        /* yb + yd */
        Ybplusd = ybIn + ydIn;

        /*  index calculation for the coefficients */
        ia2 = ia1 + ia1;
        co2 = pCoef[ia2 * 2u];
        si2 = pCoef[(ia2 * 2u) + 1u];

        /* xa - xc */
        Xaminusc = xaIn - xcIn;
        /* xb - xd */
        Xbminusd = xbIn - xdIn;
        /* ya - yc */
        Yaminusc = yaIn - ycIn;
        /* yb - yd */
        Ybminusd = ybIn - ydIn;

        /* xa' = xa + xb + xc + xd */
        pSrc[(2u * i0)] = Xaplusc + Xbplusd;
        /* ya' = ya + yb + yc + yd */
        pSrc[(2u * i0) + 1u] = Yaplusc + Ybplusd;

        /* (xa - xc) + (yb - yd) */
        Xb12C_out = (Xaminusc + Ybminusd);
        /* (ya - yc) + (xb - xd) */
        Yb12C_out = (Yaminusc - Xbminusd);
        /* (xa + xc) - (xb + xd) */
        Xc12C_out = (Xaplusc - Xbplusd);
        /* (ya + yc) - (yb + yd) */
        Yc12C_out = (Yaplusc - Ybplusd);
        /* (xa - xc) - (yb - yd) */
        Xd12C_out = (Xaminusc - Ybminusd);
        /* (ya - yc) + (xb - xd) */
        Yd12C_out = (Xbminusd + Yaminusc);

        co1 = pCoef[ia1 * 2u];
        si1 = pCoef[(ia1 * 2u) + 1u];

        /*  index calculation for the coefficients */
        ia3 = ia2 + ia1;
        co3 = pCoef[ia3 * 2u];
        si3 = pCoef[(ia3 * 2u) + 1u];

        Xb12_out = Xb12C_out * co1;
        Yb12_out = Yb12C_out * co1;
        Xc12_out = Xc12C_out * co2;
        Yc12_out = Yc12C_out * co2;
        Xd12_out = Xd12C_out * co3;
        Yd12_out = Yd12C_out * co3;

        /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
        //Xb12_out -= Yb12C_out * si1;
        p0 = Yb12C_out * si1;
        /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
        //Yb12_out += Xb12C_out * si1;
        p1 = Xb12C_out * si1;
        /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
        //Xc12_out -= Yc12C_out * si2;
        p2 = Yc12C_out * si2;
        /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
        //Yc12_out += Xc12C_out * si2;
        p3 = Xc12C_out * si2;
        /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
        //Xd12_out -= Yd12C_out * si3;
        p4 = Yd12C_out * si3;
        /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
        //Yd12_out += Xd12C_out * si3;
        p5 = Xd12C_out * si3;

        Xb12_out += p0;
        Yb12_out -= p1;
        Xc12_out += p2;
        Yc12_out -= p3;
        Xd12_out += p4;
        Yd12_out -= p5;

        /* xc' = (xa-xb+xc-xd)co2 + (ya-yb+yc-yd)(si2) */
        pSrc[2u * i1] = Xc12_out;

        /* yc' = (ya-yb+yc-yd)co2 - (xa-xb+xc-xd)(si2) */
        pSrc[(2u * i1) + 1u] = Yc12_out;

        /* xb' = (xa+yb-xc-yd)co1 + (ya-xb-yc+xd)(si1) */
        pSrc[2u * i2] = Xb12_out;

        /* yb' = (ya-xb-yc+xd)co1 - (xa+yb-xc-yd)(si1) */
        pSrc[(2u * i2) + 1u] = Yb12_out;

        /* xd' = (xa-yb-xc+yd)co3 + (ya+xb-yc-xd)(si3) */
        pSrc[2u * i3] = Xd12_out;

        /* yd' = (ya+xb-yc-xd)co3 - (xa-yb-xc+yd)(si3) */
        pSrc[(2u * i3) + 1u] = Yd12_out;

        /*  Twiddle coefficients index modifier */
        ia1 += twidCoefModifier;

        /*  Updating input index */
        i0++;

    }
    while(--j);

    twidCoefModifier <<= 2u;

    /*  Calculation of second stage to excluding last stage */
    for (k = fftLen >> 2u; k > 4u; k >>= 2u)
    {
        /*  Initializations for the first stage */
        n1 = n2;
        n2 >>= 2u;
        ia1 = 0u;

        /*  Calculation of first stage */
        j = 0;
        do
        {
            /*  index calculation for the coefficients */
            ia2 = ia1 + ia1;
            ia3 = ia2 + ia1;
            co1 = pCoef[ia1 * 2u];
            si1 = pCoef[(ia1 * 2u) + 1u];
            co2 = pCoef[ia2 * 2u];
            si2 = pCoef[(ia2 * 2u) + 1u];
            co3 = pCoef[ia3 * 2u];
            si3 = pCoef[(ia3 * 2u) + 1u];

            /*  Twiddle coefficients index modifier */
            ia1 += twidCoefModifier;

            i0 = j;
            do
            {
                /*  index calculation for the input as, */
                /*  pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
                i1 = i0 + n2;
                i2 = i1 + n2;
                i3 = i2 + n2;

                xaIn = pSrc[(2u * i0)];
                yaIn = pSrc[(2u * i0) + 1u];

                xbIn = pSrc[(2u * i1)];
                ybIn = pSrc[(2u * i1) + 1u];

                xcIn = pSrc[(2u * i2)];
                ycIn = pSrc[(2u * i2) + 1u];

                xdIn = pSrc[(2u * i3)];
                ydIn = pSrc[(2u * i3) + 1u];

                /* xa - xc */
                Xaminusc = xaIn - xcIn;
                /* (xb - xd) */
                Xbminusd = xbIn - xdIn;
                /* ya - yc */
                Yaminusc = yaIn - ycIn;
                /* (yb - yd) */
                Ybminusd = ybIn - ydIn;

                /* xa + xc */
                Xaplusc = xaIn + xcIn;
                /* xb + xd */
                Xbplusd = xbIn + xdIn;
                /* ya + yc */
                Yaplusc = yaIn + ycIn;
                /* yb + yd */
                Ybplusd = ybIn + ydIn;

                /* (xa - xc) + (yb - yd) */
                Xb12C_out = (Xaminusc + Ybminusd);
                /* (ya - yc) -  (xb - xd) */
                Yb12C_out = (Yaminusc - Xbminusd);
                /* xa + xc -(xb + xd) */
                Xc12C_out = (Xaplusc - Xbplusd);
                /* (ya + yc) - (yb + yd) */
                Yc12C_out = (Yaplusc - Ybplusd);
                /* (xa - xc) - (yb - yd) */
                Xd12C_out = (Xaminusc - Ybminusd);
                /* (ya - yc) +  (xb - xd) */
                Yd12C_out = (Xbminusd + Yaminusc);

                pSrc[(2u * i0)] = Xaplusc + Xbplusd;
                pSrc[(2u * i0) + 1u] = Yaplusc + Ybplusd;

                Xb12_out = Xb12C_out * co1;
                Yb12_out = Yb12C_out * co1;
                Xc12_out = Xc12C_out * co2;
                Yc12_out = Yc12C_out * co2;
                Xd12_out = Xd12C_out * co3;
                Yd12_out = Yd12C_out * co3;

                /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
                //Xb12_out -= Yb12C_out * si1;
                p0 = Yb12C_out * si1;
                /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
                //Yb12_out += Xb12C_out * si1;
                p1 = Xb12C_out * si1;
                /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
                //Xc12_out -= Yc12C_out * si2;
                p2 = Yc12C_out * si2;
                /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
                //Yc12_out += Xc12C_out * si2;
                p3 = Xc12C_out * si2;
                /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
                //Xd12_out -= Yd12C_out * si3;
                p4 = Yd12C_out * si3;
                /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
                //Yd12_out += Xd12C_out * si3;
                p5 = Xd12C_out * si3;

                Xb12_out += p0;
                Yb12_out -= p1;
                Xc12_out += p2;
                Yc12_out -= p3;
                Xd12_out += p4;
                Yd12_out -= p5;

                /* xc' = (xa-xb+xc-xd)co2 + (ya-yb+yc-yd)(si2) */
                pSrc[2u * i1] = Xc12_out;

                /* yc' = (ya-yb+yc-yd)co2 - (xa-xb+xc-xd)(si2) */
                pSrc[(2u * i1) + 1u] = Yc12_out;

                /* xb' = (xa+yb-xc-yd)co1 + (ya-xb-yc+xd)(si1) */
                pSrc[2u * i2] = Xb12_out;

                /* yb' = (ya-xb-yc+xd)co1 - (xa+yb-xc-yd)(si1) */
                pSrc[(2u * i2) + 1u] = Yb12_out;

                /* xd' = (xa-yb-xc+yd)co3 + (ya+xb-yc-xd)(si3) */
                pSrc[2u * i3] = Xd12_out;

                /* yd' = (ya+xb-yc-xd)co3 - (xa-yb-xc+yd)(si3) */
                pSrc[(2u * i3) + 1u] = Yd12_out;

                i0 += n1;
            }
            while(i0 < fftLen);
            j++;
        }
        while(j <= (n2 - 1u));
        twidCoefModifier <<= 2u;
    }

    j = fftLen >> 2;
    ptr1 = &pSrc[0];

    /*  Calculations of last stage */
    do
    {
        xaIn = ptr1[0];
        yaIn = ptr1[1];
        xbIn = ptr1[2];
        ybIn = ptr1[3];
        xcIn = ptr1[4];
        ycIn = ptr1[5];
        xdIn = ptr1[6];
        ydIn = ptr1[7];

        /* xa + xc */
        Xaplusc = xaIn + xcIn;

        /* xa - xc */
        Xaminusc = xaIn - xcIn;

        /* ya + yc */
        Yaplusc = yaIn + ycIn;

        /* ya - yc */
        Yaminusc = yaIn - ycIn;

        /* xb + xd */
        Xbplusd = xbIn + xdIn;

        /* yb + yd */
        Ybplusd = ybIn + ydIn;

        /* (xb-xd) */
        Xbminusd = xbIn - xdIn;

        /* (yb-yd) */
        Ybminusd = ybIn - ydIn;

        /* xa' = xa + xb + xc + xd */
        a0 = (Xaplusc + Xbplusd);
        /* ya' = ya + yb + yc + yd */
        a1 = (Yaplusc + Ybplusd);
        /* xc' = (xa-xb+xc-xd) */
        a2 = (Xaplusc - Xbplusd);
        /* yc' = (ya-yb+yc-yd) */
        a3 = (Yaplusc - Ybplusd);
        /* xb' = (xa+yb-xc-yd) */
        a4 = (Xaminusc + Ybminusd);
        /* yb' = (ya-xb-yc+xd) */
        a5 = (Yaminusc - Xbminusd);
        /* xd' = (xa-yb-xc+yd)) */
        a6 = (Xaminusc - Ybminusd);
        /* yd' = (ya+xb-yc-xd) */
        a7 = (Xbminusd + Yaminusc);

        ptr1[0] = a0;
        ptr1[1] = a1;
        ptr1[2] = a2;
        ptr1[3] = a3;
        ptr1[4] = a4;
        ptr1[5] = a5;
        ptr1[6] = a6;
        ptr1[7] = a7;

        /* increment pointer by 8 */
        ptr1 += 8u;
    }
    while(--j);

#else

    float32_t t1, t2, r1, r2, s1, s2;

    /* Run the below code for Cortex-M0 */

    /*  Initializations for the fft calculation */
    n2 = fftLen;
    n1 = n2;
    for (k = fftLen; k > 1u; k >>= 2u)
    {
        /*  Initializations for the fft calculation */
        n1 = n2;
        n2 >>= 2u;
        ia1 = 0u;

        /*  FFT Calculation */
        j = 0;
        do
        {
            /*  index calculation for the coefficients */
            ia2 = ia1 + ia1;
            ia3 = ia2 + ia1;
            co1 = pCoef[ia1 * 2u];
            si1 = pCoef[(ia1 * 2u) + 1u];
            co2 = pCoef[ia2 * 2u];
            si2 = pCoef[(ia2 * 2u) + 1u];
            co3 = pCoef[ia3 * 2u];
            si3 = pCoef[(ia3 * 2u) + 1u];

            /*  Twiddle coefficients index modifier */
            ia1 = ia1 + twidCoefModifier;

            i0 = j;
            do
            {
                /*  index calculation for the input as, */
                /*  pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
                i1 = i0 + n2;
                i2 = i1 + n2;
                i3 = i2 + n2;

                /* xa + xc */
                r1 = pSrc[(2u * i0)] + pSrc[(2u * i2)];

                /* xa - xc */
                r2 = pSrc[(2u * i0)] - pSrc[(2u * i2)];

                /* ya + yc */
                s1 = pSrc[(2u * i0) + 1u] + pSrc[(2u * i2) + 1u];

                /* ya - yc */
                s2 = pSrc[(2u * i0) + 1u] - pSrc[(2u * i2) + 1u];

                /* xb + xd */
                t1 = pSrc[2u * i1] + pSrc[2u * i3];

                /* xa' = xa + xb + xc + xd */
                pSrc[2u * i0] = r1 + t1;

                /* xa + xc -(xb + xd) */
                r1 = r1 - t1;

                /* yb + yd */
                t2 = pSrc[(2u * i1) + 1u] + pSrc[(2u * i3) + 1u];

                /* ya' = ya + yb + yc + yd */
                pSrc[(2u * i0) + 1u] = s1 + t2;

                /* (ya + yc) - (yb + yd) */
                s1 = s1 - t2;

                /* (yb - yd) */
                t1 = pSrc[(2u * i1) + 1u] - pSrc[(2u * i3) + 1u];

                /* (xb - xd) */
                t2 = pSrc[2u * i1] - pSrc[2u * i3];

                /* xc' = (xa-xb+xc-xd)co2 + (ya-yb+yc-yd)(si2) */
                pSrc[2u * i1] = (r1 * co2) + (s1 * si2);

                /* yc' = (ya-yb+yc-yd)co2 - (xa-xb+xc-xd)(si2) */
                pSrc[(2u * i1) + 1u] = (s1 * co2) - (r1 * si2);

                /* (xa - xc) + (yb - yd) */
                r1 = r2 + t1;

                /* (xa - xc) - (yb - yd) */
                r2 = r2 - t1;

                /* (ya - yc) -  (xb - xd) */
                s1 = s2 - t2;

                /* (ya - yc) +  (xb - xd) */
                s2 = s2 + t2;

                /* xb' = (xa+yb-xc-yd)co1 + (ya-xb-yc+xd)(si1) */
                pSrc[2u * i2] = (r1 * co1) + (s1 * si1);

                /* yb' = (ya-xb-yc+xd)co1 - (xa+yb-xc-yd)(si1) */
                pSrc[(2u * i2) + 1u] = (s1 * co1) - (r1 * si1);

                /* xd' = (xa-yb-xc+yd)co3 + (ya+xb-yc-xd)(si3) */
                pSrc[2u * i3] = (r2 * co3) + (s2 * si3);

                /* yd' = (ya+xb-yc-xd)co3 - (xa-yb-xc+yd)(si3) */
                pSrc[(2u * i3) + 1u] = (s2 * co3) - (r2 * si3);

                i0 += n1;
            }
            while( i0 < fftLen);
            j++;
        }
        while(j <= (n2 - 1u));
        twidCoefModifier <<= 2u;
    }

#endif /* #ifndef ARM_MATH_CM0_FAMILY_FAMILY */

}

/*
* @brief  Core function for the floating-point CIFFT butterfly process.
* @param[in, out] *pSrc            points to the in-place buffer of floating-point data type.
* @param[in]      fftLen           length of the FFT.
* @param[in]      *pCoef           points to twiddle coefficient buffer.
* @param[in]      twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.
* @param[in]      onebyfftLen      value of 1/fftLen.
* @return none.
*/

void arm_radix4_butterfly_inverse_f32(
    float32_t *pSrc,
    uint16_t fftLen,
    float32_t *pCoef,
    uint16_t twidCoefModifier,
    float32_t onebyfftLen)
{
    float32_t co1, co2, co3, si1, si2, si3;
    uint32_t ia1, ia2, ia3;
    uint32_t i0, i1, i2, i3;
    uint32_t n1, n2, j, k;

#ifndef ARM_MATH_CM0_FAMILY_FAMILY

    float32_t xaIn, yaIn, xbIn, ybIn, xcIn, ycIn, xdIn, ydIn;
    float32_t Xaplusc, Xbplusd, Yaplusc, Ybplusd, Xaminusc, Xbminusd, Yaminusc,
              Ybminusd;
    float32_t Xb12C_out, Yb12C_out, Xc12C_out, Yc12C_out, Xd12C_out, Yd12C_out;
    float32_t Xb12_out, Yb12_out, Xc12_out, Yc12_out, Xd12_out, Yd12_out;
    float32_t *ptr1;
    float32_t p0, p1, p2, p3, p4, p5, p6, p7;
    float32_t a0, a1, a2, a3, a4, a5, a6, a7;


    /*  Initializations for the first stage */
    n2 = fftLen;
    n1 = n2;

    /* n2 = fftLen/4 */
    n2 >>= 2u;
    i0 = 0u;
    ia1 = 0u;

    j = n2;

    /*  Calculation of first stage */
    do
    {
        /*  index calculation for the input as, */
        /*  pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
        i1 = i0 + n2;
        i2 = i1 + n2;
        i3 = i2 + n2;

        /*  Butterfly implementation */
        xaIn = pSrc[(2u * i0)];
        yaIn = pSrc[(2u * i0) + 1u];

        xcIn = pSrc[(2u * i2)];
        ycIn = pSrc[(2u * i2) + 1u];

        xbIn = pSrc[(2u * i1)];
        ybIn = pSrc[(2u * i1) + 1u];

        xdIn = pSrc[(2u * i3)];
        ydIn = pSrc[(2u * i3) + 1u];

        /* xa + xc */
        Xaplusc = xaIn + xcIn;
        /* xb + xd */
        Xbplusd = xbIn + xdIn;
        /* ya + yc */
        Yaplusc = yaIn + ycIn;
        /* yb + yd */
        Ybplusd = ybIn + ydIn;

        /*  index calculation for the coefficients */
        ia2 = ia1 + ia1;
        co2 = pCoef[ia2 * 2u];
        si2 = pCoef[(ia2 * 2u) + 1u];

        /* xa - xc */
        Xaminusc = xaIn - xcIn;
        /* xb - xd */
        Xbminusd = xbIn - xdIn;
        /* ya - yc */
        Yaminusc = yaIn - ycIn;
        /* yb - yd */
        Ybminusd = ybIn - ydIn;

        /* xa' = xa + xb + xc + xd */
        pSrc[(2u * i0)] = Xaplusc + Xbplusd;

        /* ya' = ya + yb + yc + yd */
        pSrc[(2u * i0) + 1u] = Yaplusc + Ybplusd;

        /* (xa - xc) - (yb - yd) */
        Xb12C_out = (Xaminusc - Ybminusd);
        /* (ya - yc) + (xb - xd) */
        Yb12C_out = (Yaminusc + Xbminusd);
        /* (xa + xc) - (xb + xd) */
        Xc12C_out = (Xaplusc - Xbplusd);
        /* (ya + yc) - (yb + yd) */
        Yc12C_out = (Yaplusc - Ybplusd);
        /* (xa - xc) + (yb - yd) */
        Xd12C_out = (Xaminusc + Ybminusd);
        /* (ya - yc) - (xb - xd) */
        Yd12C_out = (Yaminusc - Xbminusd);

        co1 = pCoef[ia1 * 2u];
        si1 = pCoef[(ia1 * 2u) + 1u];

        /*  index calculation for the coefficients */
        ia3 = ia2 + ia1;
        co3 = pCoef[ia3 * 2u];
        si3 = pCoef[(ia3 * 2u) + 1u];

        Xb12_out = Xb12C_out * co1;
        Yb12_out = Yb12C_out * co1;
        Xc12_out = Xc12C_out * co2;
        Yc12_out = Yc12C_out * co2;
        Xd12_out = Xd12C_out * co3;
        Yd12_out = Yd12C_out * co3;

        /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
        //Xb12_out -= Yb12C_out * si1;
        p0 = Yb12C_out * si1;
        /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
        //Yb12_out += Xb12C_out * si1;
        p1 = Xb12C_out * si1;
        /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
        //Xc12_out -= Yc12C_out * si2;
        p2 = Yc12C_out * si2;
        /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
        //Yc12_out += Xc12C_out * si2;
        p3 = Xc12C_out * si2;
        /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
        //Xd12_out -= Yd12C_out * si3;
        p4 = Yd12C_out * si3;
        /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
        //Yd12_out += Xd12C_out * si3;
        p5 = Xd12C_out * si3;

        Xb12_out -= p0;
        Yb12_out += p1;
        Xc12_out -= p2;
        Yc12_out += p3;
        Xd12_out -= p4;
        Yd12_out += p5;

        /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
        pSrc[2u * i1] = Xc12_out;

        /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
        pSrc[(2u * i1) + 1u] = Yc12_out;

        /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
        pSrc[2u * i2] = Xb12_out;

        /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
        pSrc[(2u * i2) + 1u] = Yb12_out;

        /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
        pSrc[2u * i3] = Xd12_out;

        /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
        pSrc[(2u * i3) + 1u] = Yd12_out;

        /*  Twiddle coefficients index modifier */
        ia1 = ia1 + twidCoefModifier;

        /*  Updating input index */
        i0 = i0 + 1u;

    }
    while(--j);

    twidCoefModifier <<= 2u;

    /*  Calculation of second stage to excluding last stage */
    for (k = fftLen >> 2u; k > 4u; k >>= 2u)
    {
        /*  Initializations for the first stage */
        n1 = n2;
        n2 >>= 2u;
        ia1 = 0u;

        /*  Calculation of first stage */
        j = 0;
        do
        {
            /*  index calculation for the coefficients */
            ia2 = ia1 + ia1;
            ia3 = ia2 + ia1;
            co1 = pCoef[ia1 * 2u];
            si1 = pCoef[(ia1 * 2u) + 1u];
            co2 = pCoef[ia2 * 2u];
            si2 = pCoef[(ia2 * 2u) + 1u];
            co3 = pCoef[ia3 * 2u];
            si3 = pCoef[(ia3 * 2u) + 1u];

            /*  Twiddle coefficients index modifier */
            ia1 = ia1 + twidCoefModifier;

            i0 = j;
            do
            {
                /*  index calculation for the input as, */
                /*  pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
                i1 = i0 + n2;
                i2 = i1 + n2;
                i3 = i2 + n2;

                xaIn = pSrc[(2u * i0)];
                yaIn = pSrc[(2u * i0) + 1u];

                xbIn = pSrc[(2u * i1)];
                ybIn = pSrc[(2u * i1) + 1u];

                xcIn = pSrc[(2u * i2)];
                ycIn = pSrc[(2u * i2) + 1u];

                xdIn = pSrc[(2u * i3)];
                ydIn = pSrc[(2u * i3) + 1u];

                /* xa - xc */
                Xaminusc = xaIn - xcIn;
                /* (xb - xd) */
                Xbminusd = xbIn - xdIn;
                /* ya - yc */
                Yaminusc = yaIn - ycIn;
                /* (yb - yd) */
                Ybminusd = ybIn - ydIn;

                /* xa + xc */
                Xaplusc = xaIn + xcIn;
                /* xb + xd */
                Xbplusd = xbIn + xdIn;
                /* ya + yc */
                Yaplusc = yaIn + ycIn;
                /* yb + yd */
                Ybplusd = ybIn + ydIn;

                /* (xa - xc) - (yb - yd) */
                Xb12C_out = (Xaminusc - Ybminusd);
                /* (ya - yc) +  (xb - xd) */
                Yb12C_out = (Yaminusc + Xbminusd);
                /* xa + xc -(xb + xd) */
                Xc12C_out = (Xaplusc - Xbplusd);
                /* (ya + yc) - (yb + yd) */
                Yc12C_out = (Yaplusc - Ybplusd);
                /* (xa - xc) + (yb - yd) */
                Xd12C_out = (Xaminusc + Ybminusd);
                /* (ya - yc) -  (xb - xd) */
                Yd12C_out = (Yaminusc - Xbminusd);

                pSrc[(2u * i0)] = Xaplusc + Xbplusd;
                pSrc[(2u * i0) + 1u] = Yaplusc + Ybplusd;

                Xb12_out = Xb12C_out * co1;
                Yb12_out = Yb12C_out * co1;
                Xc12_out = Xc12C_out * co2;
                Yc12_out = Yc12C_out * co2;
                Xd12_out = Xd12C_out * co3;
                Yd12_out = Yd12C_out * co3;

                /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
                //Xb12_out -= Yb12C_out * si1;
                p0 = Yb12C_out * si1;
                /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
                //Yb12_out += Xb12C_out * si1;
                p1 = Xb12C_out * si1;
                /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
                //Xc12_out -= Yc12C_out * si2;
                p2 = Yc12C_out * si2;
                /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
                //Yc12_out += Xc12C_out * si2;
                p3 = Xc12C_out * si2;
                /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
                //Xd12_out -= Yd12C_out * si3;
                p4 = Yd12C_out * si3;
                /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
                //Yd12_out += Xd12C_out * si3;
                p5 = Xd12C_out * si3;

                Xb12_out -= p0;
                Yb12_out += p1;
                Xc12_out -= p2;
                Yc12_out += p3;
                Xd12_out -= p4;
                Yd12_out += p5;

                /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
                pSrc[2u * i1] = Xc12_out;

                /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
                pSrc[(2u * i1) + 1u] = Yc12_out;

                /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
                pSrc[2u * i2] = Xb12_out;

                /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
                pSrc[(2u * i2) + 1u] = Yb12_out;

                /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
                pSrc[2u * i3] = Xd12_out;

                /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
                pSrc[(2u * i3) + 1u] = Yd12_out;

                i0 += n1;
            }
            while(i0 < fftLen);
            j++;
        }
        while(j <= (n2 - 1u));
        twidCoefModifier <<= 2u;
    }
    /*  Initializations of last stage */

    j = fftLen >> 2;
    ptr1 = &pSrc[0];

    /*  Calculations of last stage */
    do
    {
        xaIn = ptr1[0];
        yaIn = ptr1[1];
        xbIn = ptr1[2];
        ybIn = ptr1[3];
        xcIn = ptr1[4];
        ycIn = ptr1[5];
        xdIn = ptr1[6];
        ydIn = ptr1[7];

        /*  Butterfly implementation */
        /* xa + xc */
        Xaplusc = xaIn + xcIn;

        /* xa - xc */
        Xaminusc = xaIn - xcIn;

        /* ya + yc */
        Yaplusc = yaIn + ycIn;

        /* ya - yc */
        Yaminusc = yaIn - ycIn;

        /* xb + xd */
        Xbplusd = xbIn + xdIn;

        /* yb + yd */
        Ybplusd = ybIn + ydIn;

        /* (xb-xd) */
        Xbminusd = xbIn - xdIn;

        /* (yb-yd) */
        Ybminusd = ybIn - ydIn;

        /* xa' = (xa+xb+xc+xd) * onebyfftLen */
        a0 = (Xaplusc + Xbplusd);
        /* ya' = (ya+yb+yc+yd) * onebyfftLen */
        a1 = (Yaplusc + Ybplusd);
        /* xc' = (xa-xb+xc-xd) * onebyfftLen */
        a2 = (Xaplusc - Xbplusd);
        /* yc' = (ya-yb+yc-yd) * onebyfftLen  */
        a3 = (Yaplusc - Ybplusd);
        /* xb' = (xa-yb-xc+yd) * onebyfftLen */
        a4 = (Xaminusc - Ybminusd);
        /* yb' = (ya+xb-yc-xd) * onebyfftLen */
        a5 = (Yaminusc + Xbminusd);
        /* xd' = (xa-yb-xc+yd) * onebyfftLen */
        a6 = (Xaminusc + Ybminusd);
        /* yd' = (ya-xb-yc+xd) * onebyfftLen */
        a7 = (Yaminusc - Xbminusd);

        p0 = a0 * onebyfftLen;
        p1 = a1 * onebyfftLen;
        p2 = a2 * onebyfftLen;
        p3 = a3 * onebyfftLen;
        p4 = a4 * onebyfftLen;
        p5 = a5 * onebyfftLen;
        p6 = a6 * onebyfftLen;
        p7 = a7 * onebyfftLen;

        /* xa' = (xa+xb+xc+xd) * onebyfftLen */
        ptr1[0] = p0;
        /* ya' = (ya+yb+yc+yd) * onebyfftLen */
        ptr1[1] = p1;
        /* xc' = (xa-xb+xc-xd) * onebyfftLen */
        ptr1[2] = p2;
        /* yc' = (ya-yb+yc-yd) * onebyfftLen  */
        ptr1[3] = p3;
        /* xb' = (xa-yb-xc+yd) * onebyfftLen */
        ptr1[4] = p4;
        /* yb' = (ya+xb-yc-xd) * onebyfftLen */
        ptr1[5] = p5;
        /* xd' = (xa-yb-xc+yd) * onebyfftLen */
        ptr1[6] = p6;
        /* yd' = (ya-xb-yc+xd) * onebyfftLen */
        ptr1[7] = p7;

        /* increment source pointer by 8 for next calculations */
        ptr1 = ptr1 + 8u;

    }
    while(--j);

#else

    float32_t t1, t2, r1, r2, s1, s2;

    /* Run the below code for Cortex-M0 */

    /*  Initializations for the first stage */
    n2 = fftLen;
    n1 = n2;

    /*  Calculation of first stage */
    for (k = fftLen; k > 4u; k >>= 2u)
    {
        /*  Initializations for the first stage */
        n1 = n2;
        n2 >>= 2u;
        ia1 = 0u;

        /*  Calculation of first stage */
        j = 0;
        do
        {
            /*  index calculation for the coefficients */
            ia2 = ia1 + ia1;
            ia3 = ia2 + ia1;
            co1 = pCoef[ia1 * 2u];
            si1 = pCoef[(ia1 * 2u) + 1u];
            co2 = pCoef[ia2 * 2u];
            si2 = pCoef[(ia2 * 2u) + 1u];
            co3 = pCoef[ia3 * 2u];
            si3 = pCoef[(ia3 * 2u) + 1u];

            /*  Twiddle coefficients index modifier */
            ia1 = ia1 + twidCoefModifier;

            i0 = j;
            do
            {
                /*  index calculation for the input as, */
                /*  pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
                i1 = i0 + n2;
                i2 = i1 + n2;
                i3 = i2 + n2;

                /* xa + xc */
                r1 = pSrc[(2u * i0)] + pSrc[(2u * i2)];

                /* xa - xc */
                r2 = pSrc[(2u * i0)] - pSrc[(2u * i2)];

                /* ya + yc */
                s1 = pSrc[(2u * i0) + 1u] + pSrc[(2u * i2) + 1u];

                /* ya - yc */
                s2 = pSrc[(2u * i0) + 1u] - pSrc[(2u * i2) + 1u];

                /* xb + xd */
                t1 = pSrc[2u * i1] + pSrc[2u * i3];

                /* xa' = xa + xb + xc + xd */
                pSrc[2u * i0] = r1 + t1;

                /* xa + xc -(xb + xd) */
                r1 = r1 - t1;

                /* yb + yd */
                t2 = pSrc[(2u * i1) + 1u] + pSrc[(2u * i3) + 1u];

                /* ya' = ya + yb + yc + yd */
                pSrc[(2u * i0) + 1u] = s1 + t2;

                /* (ya + yc) - (yb + yd) */
                s1 = s1 - t2;

                /* (yb - yd) */
                t1 = pSrc[(2u * i1) + 1u] - pSrc[(2u * i3) + 1u];

                /* (xb - xd) */
                t2 = pSrc[2u * i1] - pSrc[2u * i3];

                /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
                pSrc[2u * i1] = (r1 * co2) - (s1 * si2);

                /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
                pSrc[(2u * i1) + 1u] = (s1 * co2) + (r1 * si2);

                /* (xa - xc) - (yb - yd) */
                r1 = r2 - t1;

                /* (xa - xc) + (yb - yd) */
                r2 = r2 + t1;

                /* (ya - yc) +  (xb - xd) */
                s1 = s2 + t2;

                /* (ya - yc) -  (xb - xd) */
                s2 = s2 - t2;

                /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
                pSrc[2u * i2] = (r1 * co1) - (s1 * si1);

                /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
                pSrc[(2u * i2) + 1u] = (s1 * co1) + (r1 * si1);

                /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
                pSrc[2u * i3] = (r2 * co3) - (s2 * si3);

                /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
                pSrc[(2u * i3) + 1u] = (s2 * co3) + (r2 * si3);

                i0 += n1;
            }
            while( i0 < fftLen);
            j++;
        }
        while(j <= (n2 - 1u));
        twidCoefModifier <<= 2u;
    }
    /*  Initializations of last stage */
    n1 = n2;
    n2 >>= 2u;

    /*  Calculations of last stage */
    for (i0 = 0u; i0 <= (fftLen - n1); i0 += n1)
    {
        /*  index calculation for the input as, */
        /*  pSrc[i0 + 0], pSrc[i0 + fftLen/4], pSrc[i0 + fftLen/2], pSrc[i0 + 3fftLen/4] */
        i1 = i0 + n2;
        i2 = i1 + n2;
        i3 = i2 + n2;

        /*  Butterfly implementation */
        /* xa + xc */
        r1 = pSrc[2u * i0] + pSrc[2u * i2];

        /* xa - xc */
        r2 = pSrc[2u * i0] - pSrc[2u * i2];

        /* ya + yc */
        s1 = pSrc[(2u * i0) + 1u] + pSrc[(2u * i2) + 1u];

        /* ya - yc */
        s2 = pSrc[(2u * i0) + 1u] - pSrc[(2u * i2) + 1u];

        /* xc + xd */
        t1 = pSrc[2u * i1] + pSrc[2u * i3];

        /* xa' = xa + xb + xc + xd */
        pSrc[2u * i0] = (r1 + t1) * onebyfftLen;

        /* (xa + xb) - (xc + xd) */
        r1 = r1 - t1;

        /* yb + yd */
        t2 = pSrc[(2u * i1) + 1u] + pSrc[(2u * i3) + 1u];

        /* ya' = ya + yb + yc + yd */
        pSrc[(2u * i0) + 1u] = (s1 + t2) * onebyfftLen;

        /* (ya + yc) - (yb + yd) */
        s1 = s1 - t2;

        /* (yb-yd) */
        t1 = pSrc[(2u * i1) + 1u] - pSrc[(2u * i3) + 1u];

        /* (xb-xd) */
        t2 = pSrc[2u * i1] - pSrc[2u * i3];

        /* xc' = (xa-xb+xc-xd)co2 - (ya-yb+yc-yd)(si2) */
        pSrc[2u * i1] = r1 * onebyfftLen;

        /* yc' = (ya-yb+yc-yd)co2 + (xa-xb+xc-xd)(si2) */
        pSrc[(2u * i1) + 1u] = s1 * onebyfftLen;

        /* (xa - xc) - (yb-yd) */
        r1 = r2 - t1;

        /* (xa - xc) + (yb-yd) */
        r2 = r2 + t1;

        /* (ya - yc) + (xb-xd) */
        s1 = s2 + t2;

        /* (ya - yc) - (xb-xd) */
        s2 = s2 - t2;

        /* xb' = (xa+yb-xc-yd)co1 - (ya-xb-yc+xd)(si1) */
        pSrc[2u * i2] = r1 * onebyfftLen;

        /* yb' = (ya-xb-yc+xd)co1 + (xa+yb-xc-yd)(si1) */
        pSrc[(2u * i2) + 1u] = s1 * onebyfftLen;

        /* xd' = (xa-yb-xc+yd)co3 - (ya+xb-yc-xd)(si3) */
        pSrc[2u * i3] = r2 * onebyfftLen;

        /* yd' = (ya+xb-yc-xd)co3 + (xa-yb-xc+yd)(si3) */
        pSrc[(2u * i3) + 1u] = s2 * onebyfftLen;
    }

#endif /* #ifndef ARM_MATH_CM0_FAMILY_FAMILY */
}

/**
* @addtogroup ComplexFFT
* @{
*/

/**
* @details
* @brief Processing function for the floating-point Radix-4 CFFT/CIFFT.
* @deprecated Do not use this function.  It has been superseded by \ref arm_cfft_f32 and will be removed
* in the future.
* @param[in]      *S    points to an instance of the floating-point Radix-4 CFFT/CIFFT structure.
* @param[in, out] *pSrc points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place.
* @return none.
*/

void arm_cfft_radix4_f32(
    const arm_cfft_radix4_instance_f32 *S,
    float32_t *pSrc)
{

    if(S->ifftFlag == 1u)
    {
        /*  Complex IFFT radix-4  */
        arm_radix4_butterfly_inverse_f32(pSrc, S->fftLen, S->pTwiddle,
                                         S->twidCoefModifier, S->onebyfftLen);
    }
    else
    {
        /*  Complex FFT radix-4  */
        arm_radix4_butterfly_f32(pSrc, S->fftLen, S->pTwiddle,
                                 S->twidCoefModifier);
    }

    if(S->bitReverseFlag == 1u)
    {
        /*  Bit Reversal */
        arm_bitreversal_f32(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable);
    }

}

/**
* @} end of ComplexFFT group
*/

